Evaluation of characters



April 30, 1963 EVALUATION OF CHARACTERS Filed. May 16, 1958 6 Sheets-Sheet 1 @fi a 6 v O L o 8 (0000000000) 0 O o g) l 8 o O O o A O O O 0 [39-1 mg Big- 1 2 5 AMPLIFIER 4 U T" o 5 BAND-PASS FILTER LIIMITER 9.4

6 5 R AMPLIFIE,R/ 7 c T4 C E1 OR 0 CU o 0 INVENTORS Ksteinhm 'Hfndns'uloru K. STEINBUCH ETAL 3,088,097

April 30, 1963 K. STEINBUCH -ETAL ;0

EVALUATION OF CHARACTERS Filed May 16, 1958 6 Sheets-Sheet 2 O U 0 0 m m mu m m m mu mos n+0 mu mm mu INVENTORS KStdrhzh'HEndeS-UZOHI }1. AT TOR N E) April 30, 1963 I K. STEINBUCH ETAL 3,088,097

EVALUATION OF CHARACTERS Filed May 16, 1958 a Sheets-Sheet :s

14 15 1 -4'IMEDELAY TIMEDELAY- 1 I Tzoumsa [HQ- COUNTER/ INVENTORS mswnmh-nfmum ATTOEEY April 30, 1963 K. STEINBUCH ETAL 3,088,097 4 EVALUATION OF CHARACTERS Filed May 16, 1958 6 Sheets-Sheet 4 m m m m E ua'zu .ua m

O1- O1 o1 o 1 1Q M/KLIPQFLOPQJ I E .OR E r l COUNTER 16 INVENTORS nstemumimmlaw BY W ATTO NEY April 30, 1963 K. SVTEINBUCH ETAL 3,088,097

EVALUATION OF CHARACTERS Filed May 16, 1958 I I a Sheets-Sheet 5 U- Q AMPLITUDE DISCRIMINATOR msteimm fififiw BY 2 r ATTOR NEY United States Patent 3,088,097 EVALUATION F CHARACTERS Karl Steinbuch, Fellhach, Hermann Entlres, Stuttgart- Muhlhausen, and Ulrich Zorli, Stuttgart-Zuitenhausen, Germany, assignors to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Filed May 16, 1958, Ser. No. 735,845 Claims priority, application Germany May 17, N57

11 Claims. (Cl. 340-4463) The present invention relates to a method for the mechanical evaluation of characters, in particular of printed characters.

The conventional methods for the mechanical identification of characters mostly operate according to the principle of scanning certain parts of the character either photoelectrically, magnetically or electrically. The points of scanning are selected so that a characteristic code of the scanning positions will result for the individual characters. This code however, is generally completely chosen at will and, therefore, is hard to follow up.

In another conventional method the contours of the characters are scanned with the aid of suitable means.

This method however, is very sensitive with respect to faulty discontinuances of the characters. On the other hand very bulky evaluating circuits are also required for the identification of such characters.

Also a lot of other methods, not particularly mentioned herein, bear various disadvantages, which are reduced or eliminated by the invention which uses a new evaluating principle. According to the invention the characters are divided into shape elements appearing in a random arrangement and arbitrarily often, and that thereupon, with the aid of suitable scanning means, the shape elements are examined with respect to their arrangement and frequency.

Particularly suited to the scanning purpose is a row of photoelectric cells which is moved in a certain direction relative to the characters. This row of photocells, for example, may be arranged in parallel with the longitudinal expansion of the characters and may then be led over the characters vertically in relation thereto. It is also possible to arrange the row of photocells in a stationary manner and to move the characters correspondingly, or to arrange both of them stationarily and to guide the optical arrangement of a dash-shaped light source in the desired manner over the field of characters.

It is appropriate to digitalize the photocell signals, i.e. to make the arrangement in such a way that only two definite potentials are used for the evaluation. This may be accomplished with the aid of a limiter, the output or initial potential normally being zero, while a certain percentage of the scanned black portions giving and retaining the fixed value U. In this way the shape elements are capable of being ascertained with the aid of relatively simple logical circuits.

Upon the relative movement of the scanning arrangement it becomes very easy to ascertain the timely order of succession, the position, and the frequency of the shape elements. The selection of the shape elements depends on the characters to be evaluated and is to be made in such a way that with the aid thereof the characters can .be recognized unambiguously. When employing a row of photocells or a dash-shaped light source, the timely succeeding number of intersections of the light source with the contours of the characters may be used as an additional characteristic for the unambiguous identification of the characters.

When employing this last mentioned criterion it is suiii- .cient for the identification of the figures to split them into the four shape elements.

3,638,097 Patented Apr. 30, 1963 In the following the intersecting criterion will be denoted as the shape element E. Generally all of the shape elements may appear simultaneously as well as also several times in a timely succession in the course of the scanning operation. For this reason the arrangement for carrying out the invention has to be capable, under consideration of the time succession, of recognizing the shape elements, of counting the frequency thereof within the corresponding time interval, and of assigning them to the proper figure.

The arrangement according to the invention will now be described with reference to FIGS. 1-12 by means of the example of recognizing or identifying the figures 0 9. In the appended drawings:

FIG. 1 shows a figure field with a vertical row of photocells,

FIG. 2 shows a figure field with a slantingly arranged row of photocells, 7

FIG. 3 shows a figure held with a horizontal row of photocells,

FIG. 4 shows an amplifier arrangement for a photocell,

FIG. 5 shows the figures 0 9 as well as the shape elements to the invention,

FIG. 6 shows an arrangement for identifying the shape element A,

FIG. 7 shows an arrangement for identifying the shape element B,

FIG. 8 shows an arrangement for identifying both the shape clement C and the shape element D,

FIG. 9 shows an arrangement for distinguishing between simultaneously appearing shape elements of the same type,

FIG. 10 shows an arrangement for identifying the shape element E,

FIG. 11 shows, in a detailed representation, the discriminator as shown in FIGURE 10, and

FIG. 12 shows the total arrangement for the identification of characters in a schematical representation.

For the scanning of the characters a number of lightsensitive cells are led over the character in a direction as indicated by the arrow, which cells respectively respond to the dark or bright portions of the character lying beneath. The row of photocells may be led over the field of the characters in various manners. Some corresponding possibilities are shown in FIGS. 1-3 of the drawings. In the following description however, it is assumed that the row :of photocells is arranged in the way shown in FIG. 1. Of course, instead of photocells any other type of photoelectric transducer may be used.

Since generally differences in size exist between the character extension and the dimensions of the photocells, it may be appropriate in some cases to carry out an optical representation of the character upon the row of photocells. In this case both the row of photocells and the field of the character have to be moved in relation to each other. Thereby it is basically the same whether the row of photocells is moved and the field of the character remains stationary, or vice versa. It is also possible to retain both of them and to move the optical image of a dash-shaped source of light in the desired manner over the field of the character. The adjustment of the row of photocells upon the field of the respective character is accomplished with the aid of conventional means and is assumed herein as already having been carried out, so that all parts of the character will be encountered by some photocell of the row in the course of the scanning process. Since minor displacements of the character in the direc- 3 tion of its longitudinal extension are likely to happen, the lengths of the row of photocells is somewhat greater than the possible longitudinal extension of the charact-ers.

The photoelectric devices are arranged in such a way that each will make one only of two statements, so that accordingly it is possible to evaluate the characters by means of logical circuits. The photocells are capable of making either the statement black or White. However, since the entire surface area of the photocells will not be black or white in all cases, the percentage beyond which black and consequently also white is supposed to be determinative will have to be formulated. Furthermore it is appropriate that the photocell delivers the identification signal with respect to black after the corresponding percentage of the black portions within its surface area has existed for a predetermined period of time. This requirement is adapted to eliminate all interferences caused by small dark eontaminations within the field of the character, which for a short time may cause a substantial covering of the surface area of a photocell.

In order to meet this requirement, a band-pass filter 2 (FIG. 4) is arranged behind the photocell 1 to which filter the not-yet-digitalized indication of the photocell is fed. The upper frequency limit is chosen in such a way that small impurities or contaminations will remain without effect, whereas the lower cutoff frequency is adapted to prevent the colouring of the paper background, which is changed in the course of scanning many characters, from appearing as blackened portions. From the bandpass filter the signals are applied to the amplifier 3 in which these signals are amplified in such a Way that the limiter 4 will only be capable of delivering an output signal from a certain percentage on, e.g. from 50% of black portions onward. In the case of black portions exceeding 50%, the limiter will maintain the potential U on the output line 5, thus indicating the condition black. In this way the output signals on the output lead 5 are now digitalized, because only the two potentials O and U are capable of appearing.

It may easily happen that in case the paper background becomes darker in the course of several scanning operations, the output of a photocell will indicate the condition black, by providing the potential U, although the coverage of the surface area of the photocells by character portions is still less than would correspond to the percentage of the condition black. The still missing portions of black are simulated by the paper background within the surface area, not yet covered by a character, but which has become darker in the course of time. In order to avoid such interferences, the colouring of the paper background just existing in the interval between two characters may be determined as a white colour of reference for the scanning of the next character. This function may be carried out by the amplifier as well by means of the conventional type of clamping-circuit.

For the unambiguous identification of the figures by means of the invention they may be divided into the above mentioned five shape elements A-E. FIG. 5 shows the figures 0 9 including the assignment of the individual shape elements. Besides the shape elements, the frequency of the concurrent appearance in one figure is also decisive. The vertical separating lines in the figures provide an indication for the assignment with respect to time of the different shape elements. The repeated appearance of the same shape elements at the same time positions is indicated by the corresponding figure in front of the shape element designation.

For the identification of the shape element A, which is a horizontal dash or line, the circuit arrangement shown in FIG. 6, presenting an integration member, is suitable. Because of the existence of a horizontal dash or line, the output of at least one photocell amplifier will remain at the potential U for a longer period of time. The integrating circuit, therefore, may be arranged in such a way that the integrated voltage at the condenser C will exceed a certain threshold voltage value after a certain time, so that the threshold of the amplifier 6, normally having the voltage 0 at its output 7, will now deliver the output voltage E1. This output voltage E1 will then be independent of a further charging of the condenser C, so that accordingly, a digital characteristic for the identification of the shape element A is supplied at the output thereof.

The identification or recognition of the shape element B, that is, of the vertical line or dash, is effected with the aid of the circuit arrangement shown in FIG. 7. The output leads 5 of all photocell amplifiers are connected via the same value resistors R1 to the common resistor R2, the opposite end of which is connected to a fixed potential, e.g. 0. If it is assumed that R2 R1 then each of the output leads having the potential U, will contribute the same share towards the voltage drop across the resistor R2, so that this voltage drop will be in proportion to the number of photocells simultaneously being in the condition black. The common connecting point 8 is connected with the emitter of the transistor 9, the base electrode of which has a fixed biasing potential applied to it. This biasing potential is chosen so that the potential, which is produced by a certain number of photocells being in the condition black at the point 8, will overcome the biasing potential and will thus allow the transistor 9 to change from the non-conductive to the conductive condition. The potential relations are chosen so that this may only happen when the potential U is being supplied by so many photocells that the seizure of a vertical shape element is indicated. The through-connected transistor 9 will then deliver an output signal E2 serving as a digital identification signal for the shape element B.

The identification of the shape elements C and D by means of the circuit arrangment according to FIG. 8 is based on the following considerations:

At the intersection of the row of photocells with the front edge of a slanting line, one photocell, just changed over from the condition White to black, contains one already black and one still white neighbouring cell. The latter will then be reliably the adjacent cell, which changes its condition. The position of both, the black and the white adjacent cell of the photocells just changed over from black to white, is reversed with respect to the shape elements C and D, so that this presents the only difference for the identification of these two shape elements.

The signals of the photocells are applied via the output leads 5 to the differential elements 10. The differentiated signal is only capable of passing AND-gates 11-12 when the second input lead is given the potential U. This second input lead is now connected with the output of the respective adjacent cell, which, in the case of the shape element C or D respectively is already supposed to be black. Accordingly the AND-gates 11 serve the identification of the shape element D, while the AND- gates 12 serve the identification of the shape element C.

From FIG. 8 it will be seen that the ANDagates 11 are respectively controlled by the neighbouring cell, which in this case is the left one, and that the AND-gates 12 are controlled by the right hand neighbouring cell. Accordingly, on the output lead 13 a signal will appear at the change-over of the cell from white to black in the case of the shape element C, and a corresponding output signal will be obtained on the lead 14 in the case of the shape element D. The output signals are respectively applied to a counter 15 or 16. This counting device serves the counting of the output signals, the number of which will then serve as a measurement for the length of the line.

It is, therefore, also possible to ascertain the simultaneous presence of both shape elements. If the slope of the line is a very steep one, so that practically the shape element B will exist, then the photocells will change to each counter.

their condition rapidly, one after the other, i.e. the output pulses on the leads 13 or 14 respectively will arrive in a rapid succession. In such a case, in order to avoid the statement shape element C or shape element D, the time-delay elements 17 and 18 are arranged in precedence to the counter-s, and upon arrival of a pulse, will block the leads 13 and 14 to the next successive impulse for a certain time. If the line slope corresponding to the shape elements C and D exists, then the next pulse will follow only after the impulse line has been released again.

However, if the slope of the line is a very steep one, then each impulse will block the line to the next successive impulse following very quickly, so that during the scanning of a very steep line, only the first impulse will be admitted to the counter. Accordingly, it is ensured that the circuit arrangement according to FIG. 8 can only respond to a certain or predetermined slope of the shape elements C and D.

Two simultaneously appearing shape elements C or D respectively cannot be distinguished by this, because each of them produces a train of pulses and both trains together enter the same counter where because of the greater number of pulses, they will act like a long slanting line of the respective shape element. Under certain circumstances, this may cause a simultaneous arrival of impulses which will be counted as one only. However, it is possible to avoid this by momentarily storing the pulses behind the AND-gates 11 and 12, which are then read-oii by a quick-operating timing device, cyclically reading all pulse trains, and only thereafter are applied to the pulse counting device.

In FIG. 9 a circuit arrangement is shown which may be used for distinguishing between simultaneously appearing shape elements C and D. According to this arrangement a plurality of counters is assigned to each AND-gate 11 or 12 respectively. Each photocell disposed at the beginning of a sloping line, hence which changes over from white to black when the neighbouring cell is already black, seizes one of these counters by means of its output parts, which counter will only count the subsequent impulses of this row but not, however, the pulses of a second slantingly ascending line beginning e.g. shortly thereafter. By means of its first photocell the row of the second iine will seize the next successive idle counter, only adapted to count the impulses thereof. Accordingly, as many counting devices have to be provided as shape elements of the same kind are likely to appear concurrently. In the case of figures it is sufiicient to provide three counting devices for each of the shape elements C and D.

The seizing of the counting devices is accomplished as follows: A number of flip-flop circuits 19 corresponding to the number of photocells employed are assigned A coincidence lead 20 extends from each flip-flop circuit to a gating circuit 21 whose opposite input lead is connected with the output of the gate 11. Accordingly, the output impulse will at first have to pass the gate 21 before being admitted to the counting device 16. The output lead of each gate 21 is connected with the 0-position of all flip-flop circuits, with the exception of the neighbouring flip-flop circuit, at which circuit it is connected with the l-position thereof. Since at first all of the flip-flop circuits are in position 1, all of the gates 21 are also open. If new the first impulse extends from gate 11 via gate 21 to the counting device 16 and the flip-flop circuits 19, then all of the flip-flop circuits Will be brought into the position 0, with the exception of the neighbouring flip-flop circuit, which will remain in position 1, or will assume the position 1 in the case of having been in the position 0.

When the flip-fiop circuits proceed to the 0-position, then the corresponding gates 21 will be blocked, so that any subsequently following impulses will be prevented from passing these gates. Only the flip-flop circuit corresponding to the neighbouring photocell will remain in position 1, so that the next impulse will arrive there and will be admitted to the counting device 16. This impulse however, will return the fiip-fiop circuit to the position 0 and its next successive flip-flop circuit will be returned from 0 to 1, so that the next impulse will be admitted only at the gate 21 corresponding to that flip-flop, etc. All of the impulses however, will be applied to the same counting device 16.

As soon as the first counting device has been seized in this way by the first counted impulse, it will open the next one which, until then had been in a blocked condition like all of the other counting devices. An arrangement of the same type as described hereinbefore is associated with this counting device, so that now the same process may be repeated by involving another first cell of a further slanting line. This may be any other photocell; care must only be taken, however, that the photocell intended as the next one to be switched over in the first row, is incapable of releasing this process.

The arrangement for the shape element D (gate 12) is identical, so that there is no need for particularly describing it herein. For ascertaining the shape element E, i.e. the number of intersections between the row of photocells and the contours of the figures, the circuit arrangement according to FIGS. 10 and 11 is provided. In the case of an intersection between a line of a character and the row of photocells, two photocells will always be at the edges of the line, one of which is white and the other is black. A pair of series-connected voltage divider resistors 22 is connected between every two of the leads '5 from the photocell-s. Then the centre point 23 between two of these resistors will only assume the potential /2 U when the two adjacent photocells are in different conditions. In the case of each intersection, therefore, in the row of the photocells this potential /2 U has to be twice determinable, so that half the number of appearances of this potential will indicate the number of the momentary intersections. In order to determine in this number, the voltage dividing centree 23 are respectively connected with an amplitude discriminator 24 which only delivers an output signal 'E in the presence of the potential /2 U. These discriminator outputs are cyclically read by a quick operatmg timing device, so that the number of the intersections can be continuously determined in the course of scanning a figure.

In FIG. 11 this discriminator 24 is shown in detail. When the centre 23 of the voltage divider conducts the potential U, that is, when both cells are black, or when conducting the potential 0, that is, when both cells are white, then always one of the two transistors 25 and 26 1s conductive, provided that care has been taken for the corresponding emitter bias at the transistor 25, or respectively for the base bias at the transistor 26. As will be seen from the showing of FIG. 11 both the emitter electrode of the transistor 25 and the base electrode of the transistor 26 have the same biasing potential, while the base electrode of transistor 25 and the emitter electrode of transistor 26 are connected with the emitter electrode of the input transistor 27. Both the transistors 25 and 26 are non-conductive at the same time and only when the potential /2 U exists at the centre 23 of the voltage divider, in other words, at the base electrode of transistor 27. For this reason an output signal E will only be produced at the collector electrodes of the transistors 25 and 26 in this single case.

The described circuit arrangements are schematically shown in FIG. 12. In this representation:

V photocell amplifier comprising band-pass filter and limiter, as shown in FIG. 4,

a=integration element comprising the amplitude threshold for the shape element A, as shown in FIG. 6,

b=transistor arrangement with the characteristic base bias for the shape element B, as shown in FIG. 7,

c, d=difierentiating element comprising the AND-gate for the shape element C or D respectively, as shown in FIG. 8,

Z1, z =counting devices (counters) preceded by flip-flop seizing circuits for the shape elements C or D respectively, as shown in FIG. 9,

e=voltage divider comprising an amplitude discriminator for the shape element E, as shown in FIG. 10,

A, B, C, D, E=indicating switching for stating whether and how often the corresponding shape element exists.

The identification signals produced by the switching means AE are applied to a shape element combining means (combinator) 28 where the character is determined from the kind, number and order of succession of the respective shape elements. In the described example the shape element combinator comprises 10 output leads or outlets for the figures '0 through 9.

While we have described above the principles of our invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way ofexample and not as a limitation to the scope of our invention as set forth in the objects thereof and in the accompanying claims.

What is claimed is:

1. Apparatus for evaluating characters comprising a plurality of sensing elements mounted in a predetermined arrangement, means for presenting a character to said sensing elements and for causing relative movement of said character and sensing elements in a predetermined direction, a plurality of shape-recognition circuits, each connected to all of said sensing elements for producing an output in response to a different efiect of said sensing elements, one of said circuits comprising a plurality of ditferentiating networks, there being one connected to each said sensing element, first and second coincidence gates for each element, each having two inputs, each first gate having one input connected to said corresponding differentiating circuit, and the other input connected to the preceding sensing element, and each said second gate having one input connected to said corresponding differentiating circuit and the other input connected to the succeeding sensing element, a first counting means connected to the outputs of all of said first gates, and a second counting means connected to the outputs of all said second gates, said first counting means adapted to produce an output when a predetermined number of said first gates have produced an output when successively opened in one direction, said second counting means producing an output when a predetermined number of said second gates have produced an output when successively energized in the other direction, and said apparatus further comprising means responsive to the combination of said circuits producing an output for recognizing the character.

2. Apparatus, as defined in claim 1, further comprising a time delay circuit connected between each counting means and its corresponding gates, each time delay circuit having a time delay shorter than a predetermined repetition rate of the outputs from successively opened gates.

3. Apparatus, as defined in claim 2, further comprising a plurality of counting devices connected to each first gate, a plurality of counting devices connected to each second gate, and means for successively seizing said counting devices in response to successive signals appearing at the associated first or second gate.

4. Apparatus, as defined in claim 3, in which the means for successively seizing the counting devices comprises a plurality of auxiliary coincidence gates associated with each of said first and second gates, said auxiliary gates being connected respectively between the associated first or second gate and said counting devices, a plurality of flip-flop circuits divided into groups, there being one group for each counting device and each group having the same number of flip-flop circuits as there are sensing elements,

means for connecting the output of each auxiliary gate to the associated counting device and to the 0 side of all the associated flip-flop circuits except the next successive flip-flop circuit where said output is connected to the 1 side, one input of each auxiliary gate being connected to the output of the associated first or second gate and the other input being connected to the 1 output of the associated flip-flop circuit, whereby only that particular counting device which is seized by the first signal impulse of a train of impulses will be successively controlled by all the auxiliary gates associated with one or the other of the first and second gates.

5. Apparatus, as defined in claim 4, further comprising means in each counting device responsive to seizure thereof for unblocking the next successive counting device for receipt of a subsequent train of signal impulses from successive sensing elements.

6. Apparatus for evaluating characters comprising a plurality of sensing elements mounted in a predetermined arrangement, means for presenting a character tcgaid sensing elements and for causing relative movement of said character and sensing elements in a predetermined direction, a plurality of shape-recognition circuits, each connected to all said sensing elements for producing an output in response to a different effect of said sensing elements, one of said shape-recognition circuits comprising a plurality of resistors arranged in pairs, each pair being connected in series between adjacent sensing elements, a plurality of amplitude discriminator circuits, one being connected to the juncture of every pair of resistors, said discriminator circuits being arranged to respond when there is a response from one sensing element connected to one of a pair of resistors while there is no response from the sensing element connected to the other resistor of said pair, and said apparatus further comprising means responsive to the combination of said circuits producing an output for recognizing the character.

7. Apparatus, as defined in claim 6, in which each amplitude discriminator circuit comprises first and second transistors having their collector electrodes connected together, a third amplifying transistor, the base electrode of said first transistor and the emitter electrode of said second transistor being connected to the emitter electrode of said third transistor, means for applying the potential appearing at the junction of the associated pair of resistors to the base electrode of said third transistor, means for biasing the emitter electrode of said first transistor to a predetermined voltage value, and means for biasing the base electrode of said second transistor to a predetermined voltage value,

8. Apparatus for evaluating characters comprising a plurality of sensing elements mounted in a predetermined arrangement, means for imaging the character on said sensing elements, means for causing relative motion between said character image and said sensing elements, a plurality of shape recognition circuits connected in parallel to said sensing elements, each of the said circuits being arranged to ascertain the existence of a difierent fundamental shape, said plurality of circuits including four different types which coact to recognize five fundamental shapes and means for combining the existing fundamental shapes to identify the character.

9. Apparatus for evaluating characters comprising a plurality of sensing elements mounted in a predetermined arrangement, means for presenting a character to said sensing elements and for causing relative movement of said character and sensing elements in a predetermined direction, a plurality of shape-recognition circuits each connected to all of said sensing elements for producing an output in response to a different efiect of said sensing elements, one of said circuits comprising a transistor, means for connecting all of the sensing elements through individual resistors to the emitter electrode of said transistor, a common resistor, means for connecting said common resistor between said emitter electrode and a fixed poten- 9 tial, the values of said individual resistors being such that said transistor will become conductive when at least a predetermined number of said sensing elements are producing output signals, and said apparatus further comprising means responsive to the combination of said circuits producing an output for recognizing the character.

10. Apparatus for evaluating characters comprising a plurality of sensing elements mounted in a predetermined arrangement, means for presenting a character to said sensing elements and for causing relative movement of said character and sensing elements in a predetermined direction, a plurality of shape-recognition circuits each connected to all of said sensing elements for producing an output in response to a different effect of said sensing elements, said shape-recognition circuits being responsive to a horizontal line, a vertical line, a line slantingly ascending towards the right, and a line slantingly descending towards the right, respectively, said apparatus further comprising means responsive to the combination of said circuits producing an output for recognizing a character, means for counting the intersections of the sensing elements with portions of the character being evaluated during relative movement of said sensing elements and said character, and means for utilizing the result of said counting means in said character recognizing means.

11. Apparatus for evaluating characters comprising a plurality of sensing elements mounted in a predetermined arrangement, means for presenting a character to said sensing elements and for causing relative movement of said character and sensing elements in a predetermined direction, a plurality of shape-recognition circuits, each connected to all of said sensing elements for producing an output in response to a different effect of said sensing 10 elements, one of said shape-recognition circuits being adapted to recognize a signal corresponding to a horizontal line, another of said shape-recognition circuits being adapted to recognize a signal corresponding to a vertical line, still another of said shape-recognition circuits being adapted to recognize a signal corresponding to a line slantingly ascending towards the right and still another of said shape-recognition circuits being adapted to recognize a signal corresponding to a line slantingly descending towards the right, said apparatus further comprising means coupled to all of said shape-recognition circuits for producing an output representative of a character in response to the combined outputs of said shape-recognition circuits.

References Cited in the file of this patent UNITED STATES PATENTS 1,815,986 Parker July 28, 1931 2,616,983 Zworykin 1 Nov. 4, 1952 2,682,043 Fitch June 22, 1954 2,889,535 Rochester June 2, 1959 2,905,927 Reed Sept. 22, 1959 2,924,812 Merritt Feb. 9, 1960 2,932,006 Glauberman Apr. 5, 1960 3,000,000 Eldredge Sept. 12, 196 1 FOREIGN PATENTS 785,853 Great Britain Nov. 6, 1957 786,466 Great Britain Nov. 20, 1957 794,139 Great Britain Apr. 30, 1958 OTHER REFERENCES Publication I: Pulse Techniques, Dept. of the Army Technical Manual, TM'11-672, ch. 3, October 1951. 

8. APPARATUS FOR EVALUATING CHARACTERS COMPRISING A PLURALITY OF SENSING ELEMENTS MOUNTED IN A PREDETERMINED ARRANGEMENT, MEANS FOR IMAGING THE CHARACTER ON SAID SENSING ELEMENTS, MEANS FOR CAUSING RELATIVE MOTION BETWEEN SAID CHARACTER IMAGE AND SAID SENSING ELEMENTS, A PLURALITY OF SHAPE RECOGNITION CIRCUITS CONNECTED IN PARALLEL TO SAID SENSING ELEMENTS, EACH OF SAID CIRCUITS BEING ARRANGED TO ASCERTAIN THE EXISTENCE OF A DIFFERENT FUNDAMENTAL SHAPE, SAID PLURALITY OF CIRCUITS INCLUDING FOUR DIFFERENT TYPES WHICH COACT TO RECOGNIZE FIVE FUNDAMENTAL 